1. Field of the Invention
Insecticidal compositions comprising normally-employed insecticidally-active agents but comprising an activity-enhancing amount of capsaicin or other capsaicinoid, especially in the form of capsicum, and the insecticidal employment thereof. According to the present invention, it has been found that the employment with normally-employed insecticidally-active agents of activity-enhancing amounts of capsaicin or other capsaicinoid, especially in the form of capsicum, but also including synthetic capsaicinoids such as the vanillyl amide of pelargonic acid, produces synergistic effectiveness in combatting numerous insects, especially boll worms, beet army worms, loopers, beetles, and bud worms, in actual field applications. As used herein, the term "capsaicinoid" is broad enough to encompass capsaicin and amounts thereof contained in capsicum.
2. Prior Art
The prior art is replete with innumerable insecticidally-active agents and compositions thereof. Nevertheless, existing insecticidal agents and compositions continue to exhibit less than optimum effectiveness, especially when employed in an attempt to control certain insects, and specially upon certain living plants and crops.
Known prior art discloses the employment of capsaicinoids as insect as well as animal and human repellents. They have also been used as optional ingredients of miticides in combination with elemental sulphur plus garlic extract, as a pesticide for snails, as an ingredient of a paint on the interior of beehives or on the exterior of boats, and they have also been used as a component of aerosols for crowd control and in personal protective devices.
The following Examples show that capsaicinoids are not toxic to insects, when used alone, and the observations of the inventors in this regard is similar to the known effect of capsaicinoids on humans. For example, hot peppers of the Capsicum genus have been used as condiments in foods for centuries, and extracts thereof are classified as "GRAS" by the US Food and Drug Administration. They moreover have EPA approval for use in self-defense and crowd-control aerosols.
The prior art in this field has been searched. In two (2) separate searches conducted in United States Class 424 subclass 195.1, Class 514 subclass 627, and in the APS full-text data base, as well as in US Class 424, subclasses 45, 48, 195.1, and 405 and US Class 514 subclasses 918 and 919, the essence of the present invention was not found to be disclosed or suggested.
The most relevant US patents turned up in the searches were as follows:
U.S. Pat. No. 312,270 Hoag, issued Feb. 17, 1985:
Hoag provides a mixture of capsicum, Hellobore, Paris Green, sugar, and carbolic acid and uses this mixture as an insecticide. Paris green (copper acetoarsenite) and carbolic acid are strong poisons which would kill anything in sight, even if it was an insect, whereas it would appear that the capsicum was employed as a repellant because of its noxious properties, although such is not stated. In the presence of Paris green and carbolic acid, any insecticidal effect of capsicum would surely have been masked, if existent.
U.S. Pat. No. 436,848 Farwell, issued Sep. 23, 1890:
Farwell provides insecticides for external application to animals to avoid annoyances by insects, which preparation must not irritate the skin and which must yet retain the essentials for driving away the insects. It consists of "water-pepper", Polygonum hydropiper, which is unrelated to the Capsicum genus. It further belongs to the order Polygonacae, whereas Capsicum belongs to the order Solanaceae. The formulation of Farwell also contains wormwood, a member of the Artemisia family, which is known to be high in essential oils containing thujone. This patent in no way suggests the use of capsaicin or capsicum for its intended purpose according to the present invention.
U.S. Pat. No. 930,549 Lechner, issued Aug. 10, 1909:
Lechner claimed an insecticide comprising benzene as a solvent, poke-root, alum, and red pepper, but does not describe the purpose of the red pepper. Lechner considers the smell of the poke-root as the permanent repellent, but fails to describe the role played by the capsicum, which is not identified as an insecticide.
U.S. Pat. No. 2,159,953 Proetto, issued May 23, 1939:
Proetto prepares a combination of wine dregs, capsicum, African bitter gourd juice, nicotine, and strong alkalized soap solution for use an as insecticide. He states at Column 2, lines 46-50, that the combination of capsicum, the African bitter gourd juice, and the wine dregs constitutes a death-dealing combination of ingredients, whereas the nicotine is present as a narcotic. He goes on to state at page 2, Column 1, lines 1-4, that the nicotine and alkalized soap may be omitted in some instance, although all the claims of this patent include both of these ingredients. According to Merck Index, 11th Edition, page 6431, nicotine is a powerful commercial insecticide identified, inter alia, as "Black Leaf 40.TM.", described as being highly toxic and useful in a soap as a contact poison. The combination of capsicum, African bitter gourd juice, and wine dregs in the presence of the nicotine and soap certainly leaves the role of the individual ingredients undefined, especially since the nicotine in the presence of soap is a highly toxic ingredient. The capsicum most probably serves only as a repellant. It is not employed in oleoresin form.
U.S. Pat. No. 4,820,517 Pfeiffer, issued Apr. 11, 1989:
Pfeiffer prepares a fraction of black pepper extract which is insecticidal. This fraction is non-irritating as pointed out in his Column 1, lines 51-60, which is not a characteristic of capsaicin, which is very irritating to human beings. The active principle of Pfeiffer is of unknown composition, but black pepper Piper nigrum, is unrelated to Capsicums, and the principle in black pepper which causes "bite" is piperine, a compound which is chemically distinct from capsaicin and other capsaicinoids. Pfeiffer accordingly does not show or suggest either the compositions or the method of the present invention.
U.S. Pat. No. 5,227,162 Ferrari, issued Jul. 13, 1993:
Ferrari shows an acaracide comprising ethanol, garlic pulp, elemental sulphur, and optionally capsicum (Column 1, lines 53-68). Capsicum is present in his preferred mixture and in some of his claims. The exact role of each of the ingredients is left in doubt but, in any event, since arachnids are not insects, Ferrari can provide no showing or suggestion or either the composition or method of the present invention.
As seen from the foregoing, the searches failed to reveal previous patent literature considered to be even close to the present development and a search of the APS full-text data base was also unproductive.
A problem constantly facing farmers with the need to control insects attacking plants and crops is the slow loss of activity which insecticides develop as resistance thereto builds up. There is always a need for improved materials which are not only more effective against particular insects, but which are also versatile and can be used to combat a wide spectrum of insects. Such improvements are seldom achieved by the use of a single insecticide. Nevertheless, whether mixtures of insecticides or single individual insecticides are employed, it is always of great value to find some manner in which their insecticidal activity can be enhanced.
It has now been found that mixtures of insecticides with capsaicin or other capsaicinoid, or capsicum containing the same, have valuable and unexpected properties in that the insecticidal activity of the admixture is greater than would be expected and synergism is exhibited of a kind which is especially effective in the context of certain crops such as cotton, soybeans, and the like.
Accordingly, the present invention provides an insecticidal composition comprising an admixture of an active insecticide and an activity-enhancing amount of a compound selected from capsaicin, other capsaicinoids, and capsicum containing the same.